The present invention relates to a liquid brace.
The human body is 60% water, and relies on atmospheric pressure and containing structures such as skin and muscle to maintain its fluids within its organs and to assist in the proper circulation of these fluids. Injury that disrupts these structures can allow the escape of fluid, causing further change. For example, the skin may be damaged by heat, cold or physical force. Fluid may as a result escape from internal body structures and cause swelling, which in turn may compromise the function of other structures such as veins, compounding the effect of the original injury. Similarly, since muscles aid the return of (blood and lymphatic) fluids to the lungs and chest by creating pressure during contraction, injury to muscles can therefore create additional circulatory problems. Muscles also support the bones they surround, and injury to muscles can result in a lack of support for bone structure during everyday activities. Thus, the purpose of containing devices for fluid in an injured or malfunctioning (i.e. Varicose Veins or Lymphoedema) limb is twofold: to minimize swelling; and to provide support to the limb.
This is reflected, for example, in the design of artificial limbs, where the sockets constrict the limb to contain the fluid muscle, fat and body fluids in the stump of the limb. In an above knee stump, the force of the body directed down the thigh bone (femur) is transferred to the artificial limb through resistance by the fluid pressure created by the socket.
However, sustained pressure or compression of liquid is harmful. For example, when tissue pressure is maintained above 25 mm of mercury then effective tissue perfusion is often terminated with severe consequences, as in xe2x80x9cCompartment Syndromexe2x80x9d.
There are known benefits to healing injuries in a normal activity environment. Healing at rest allows weak and poorly structured tissue to form, which must later be modified with secondary healing and/or therapy. This runs the risk of refracture, stiff joints or permanently weak ligaments. In contrast, healing in a normal activity environment creates stronger tissue, minimizes weakening of existing tissue, and often leads to earlier recovery. The usual barriers to healing in a normal activity environment are pain caused by swelling in the injured body area as well as the need for adequate structural support provided at the proper strength and at the right time and position to support weight-bearing activities.
Therapeutically effective pressure should therefore: (1) be cyclical, (2) mimic normal tissue pressure, and so (3) allow for normal activity while healing. Specifically, the normal resting liquid pressure in a body varies with the distance of a body part from the heart. Muscles acting around a limb create tremendous supporting pressures with normal activity and are vital to the support of bone, they also resist the escape of fluids from damaged tissue, and assist in the return of liquids to the heart. Furthermore, such pressures will be created at the appropriate time, such as when a load is placed upon a limb. Braces that can create or mimic such pressures thus allowing normal activity healing would aid in the speed and quality of the healing process for acute injuries.
A known difficulty is to design a brace that easily compensates for changes in the volume of an injured limb while avoiding potentially dangerous pressures. As a result, rigid and adjustable braces require frequent adjustment to be effective and not to cause damage. The xe2x80x9ccast-bracexe2x80x9d methods address this issue with frequent cast changes to compensate for swelling, reduction and musclewasting common to all injuries.
One known pressure device for Achilles tendon inflammation (the xe2x80x9cpneumatic Achilles wrapxe2x80x9d by Aircast Incorporated(trademark)) contains air bags on either side of the Achilles tendon connected to a bag placed beneath the foot. As the patient walks, the bag beneath the foot is compressed, inflating the bags around the Achilles tendon and increasing the pressure upon the tendon. When the foot lifts, the bags beneath the foot re-inflate and the pressure on the tendon is eased. This creates a cyclical high-low pressure. The level of resting, baseline or non-dynamic pressure may be decreased by allowing some of the air to escape from the brace through an external valve.
Braces are also known (the Plexipulse(trademark) by NuTech,(trademark) or various compression units by Jobst(trademark)) that extend along the length of an entire injured limb, such as a leg. These provide a plurality of air bags around the limb, each directly coupled to an electric pump which inflates them to create pressure. The pump may inflate the air bags serially to create a gradient of cyclic pressure along the length of the limb with a set resting pressure. However, the pump assembly is relatively complicated and expensive, and the patient""s mobility is restricted when the brace is connected to the pump. This design is typically used for the treatment of chronic rather than acute injuries.
The pressures generated by these known devices may be insufficient to support injured tissues, especially during weight bearing or lifting.
The present invention provides, as part of a brace, at least one flexible compression bag, which may be partially distended with liquid, and placed against the injured body part. Through the use of valves and a pump, cyclic pressure may be created in the flexible compression bags, resulting in a cyclic pressure being applied to the injured body part.
In accordance with the present invention, there is provided a brace for supporting an injured body part of a wearer, comprising: at least one flexible compression bag adapted for holding a liquid; and a plurality of valves segmenting said at least one compression bag and arranged to provide liquid flow in a controlled manner through said at least one compression bag.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.